I'm sorry they lied to you. You really should have put a hold on your credit card immediately. I figure you probably realize that by now.

Also, think about what your password was. My WoW password is a combination of uppercase and lowercase, with numbers added in, plus I have the authenticator code feature. If XBOX offers a similar feature, even for just the few bucks it costs to mail the authenticator to you, it's worth it.

http://www.techdigest.tv/2009/04/lost_and_naked.html

"If you're a player of World of Warcraft, or any other online game, put yourself in Luke's shoes for a minute. Think about how long it took you to acquire the items that you're using in-game, and how long it would take to replace them. Then go change your account password and buy an authenticator - in the long run, you'll be very pleased you did."